The most epic PVP I was ever involved in was some of either the old Taren Mill / Southshore clobberfests back in the day, or the multiple-week-spanning AV matches back when AV first came out and had no time limit.
Battlegrounds these days is usually just a match of "who is less retarded", and doesn't actually involve any skill or strategy since 99% of people either don't care or don't know the strats to begin with. A prime example of this is pretty much every AB match I've done lately. Everyone zergs to BS, leaving no one at Farm and maybe 2-3 people to cap LM and no one at all at Mines.
Alliance will cap Stables, zerg LM, cap Mines, and then rush Farm afterwards. This results in a 4-1 loss pretty much every single time.